SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c1910dbb42df7ecf928926e774fdb3b5191812f795138a30039ca9a4e02c529' 
  AND token = 'AIhjGXJPxdxKCOyAGJfcwxGasDOFItBlYnBvnPBsuxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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