SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5af97a8ae31c2841f42ed0e0e99e154baf02208b7c224198f76ab353b78ad335' 
  AND token = '7pJUpdsD6KRFHvAZt7x+t6eNNPoz6ebsSMhRzFwALL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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