SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33bb21ac710064bf13d7db1a23e3e89d603fe86e6989513ab3c5febc2d1eb284' 
  AND token = 'OrgftPETPqbIDMssbqsXh9uXjFwx69iu23KyXWvy+iE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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