SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '90270f9e96382612372bb036a9c1502fbbf06bf3abc91133bf36cebe25689754' 
  AND token = 'qcJ8aoyhl0iSRGKme+IfDaI4QolSIaRG3HCzArc4LgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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