SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '227ed87d2569cf00c7869eae68ead510b7df948f965a683d4c9a433a326248fa' 
  AND token = 'wyRGKO5lO9QwvyGgsF4+SOwD1u+u77VVwqiIWqaptzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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