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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c950c714cc3f1c84185d157c3c696f45e76c16a1b8408b7adedd5e4f11f9db5' 
  AND token = 'tqrwzgOd7fas7ggQNzRgDIYcy3MBdCsrEerusQxFsuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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