SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35c451c1d5ac20f3031e1d584652a4ef457afaf95303c921f4d7d7a9cedd4dbb' 
  AND token = '8mUDi/UjdWSY22cAS49rgERD608eOeT2vCW3G9a8ebg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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