SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '503cab80c1805ab0508939b58ad919f30141591b013f03e71b189b4b5d282c74' 
  AND token = 'JhzRXzS5H5Zao04UkfGGBdwE78q/9D21/Rk2Zhqjp+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}