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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64efe58de9aca25fcf818f6ea7b12960e013a1e44bc87147bd7e3df25a688c78' 
  AND token = 'xBfOmf0WDpnWvL2KmQYt72mYE+8tYrhihimtE4QTqb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}