SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'daf19ce5a9d99c96c6fa187d59948c28e884f5d8b5777feec94605f1cbcd85c6' 
  AND token = 'xKjSxVDdmLYVuwf2N3dC4tZHyA88QtDvvyEsdFFeie0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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