SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b8a12ab9bbf20640a4fe36fd6ca729e6f054e9df980e9871fd7024a68e24127' 
  AND token = '65gIGywh+samEvMDSvGhHZSXgKn/pddY6tM5PLlMPu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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