SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ce9eab88854066da728dbf92a55af04b41dd4ac6685605e516ef3b1b43390f61' 
  AND token = 'I4z6cCvPub72fNCMENLlKYVBF9IWK833H9TwIqSuXtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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