SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5564414918c729ee63f44f1283142bd17d55a9920d52e03bde016b1d8c0e34e' 
  AND token = 'h1wUDTUzY3OZBpHqYnmjU7JkK4g18Ccd31it+zsRhCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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