SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ea5c80e243247264a4ad26a7a82729974b2fa26ab852cfeb43e110654ddf70f1' 
  AND token = 'lTtQd9oDzmK3tL0tlygRrzNLhWhTVeKlqkWLiCaBch4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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