SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91225e680321c93ad04732b2c1b94981d8edd3e212c6813d50693fd7b1f2a386' 
  AND token = 'mxRcR1yphg0zTKQ17T/5u55SQbgzuyXwzh5dHcUiCso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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