SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8591f27f8c29a42727eec447436ffeb38875686b8dfa99163596bad94883a867' 
  AND token = 'G3HvHoHP4axI/odqBCfb5O8YjkSsKWyZw+cweqL/t8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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