SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4b48c7077f732ed34cda030bf44c703cb0dff1e36e16cd6e296d92d50d7e44e4' 
  AND token = '1mtjv6kW3t0AS02Fcyvcxy5wvLGAgoHYr24xqv3Tyuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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