SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '661b4a0cbdb31b358b3532b8ffd13324107abad66b5d59e9d4773822a4795e5f' 
  AND token = 'ihS3f7bzZZFN2VRpUuvrPK9+vBM6VamgqcS10qkhtoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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