SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74a82b2bf0150dffb5affdc77d399290bae1c21e73023264bcd2819721d74854' 
  AND token = 'jyBZckuqOEAi7powo2BKFvNdXmLDfvYV9Z9SJoKjA20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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