SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a97d8a76274f373f65ddf468aeb0f792bb3f9b6a11b5dbe627356034ee17cb7a' 
  AND token = 'lB6c81Zh8q9cqHFZPu1un+dkRhvKwo6xqdKjRj7iuSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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