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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b248f1bb0ee35f25f083cc70b5e383ea682d0a0ab5d41a0b7f42dc920be0c73f' 
  AND token = 'F0MoBXlkEzVS0MmlzBqb0Q3e4sQtFHNKQNFF/nLen4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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