SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b22ba1e00cbff1f603b117957be8b46edd9af35c2cfb3fe9387a5f9ed4b5b499' 
  AND token = 'YEXlHLYPBKLOzZQznNWTMD0+6ocv7GI8mniByR4sv8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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