SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f229b4be7eb341ab873105f7f55afcf274d30ec60f2a76313894bce7909ba58f' 
  AND token = 'sWql5ZPRpYVSS8F7T6JZEheRE21UiOvjRFSm6PZJ/TA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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