SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '507cd4cad86da3699fa3c595e86bd9ce6100d58a2e119b51bdc20cd83c4a809c' 
  AND token = 'fQxQwyY+KXy2ku/iIBDJQ8VrqEE3bWyKZYo/9SDsGIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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