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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c57ba299311c6dd5c2eb7eba3cc5a2bdaa4c8da293589426826a6e6fe0ce6b9a' 
  AND token = 'kS3DXaY+FZ0ki7NZYAdUY8pJSzrwMEXRnUrqFcrgwmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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