SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02d0908bc38052aed662fc4aaf3f31e6b61ed44b135ad1e4c8dc1b1efb4dd4c7' 
  AND token = 'jqZbTCg/asUt8mcBykMTNTwC61BwewqsZ3to7B38Qvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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