SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a2feae6e76720338e8d703e80f7dfbd94cc447abb7cfd862aefb8ac40d032c6' 
  AND token = '8raoJVmaoLqbTIDqJXjYqoLbqUDXkV4XlIwgLcxgyPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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