SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a542e7effe70d0aed92b9dbd3fe61669c250009de9c171b9cdf63784bb6b272' 
  AND token = 'hoeN0AwrZMeTyXqKECpjOylUNBC1D4aEwhpMCUiWbDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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