SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2c0171d859989cf4c2d0ff977084201a7c80f85f0c10b612aad6663c2bc8b166' 
  AND token = 'Fu2jFh/S2/fPgaNxkG3NQ8VQq1VzA3raYs38JVvNcns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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