SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc17b8c19e161169e805204cdecd070800c9bd63af9649dcfb4a05a08b347c7f' 
  AND token = 'TVKkZfoT5x3aOQbpITc7vOuVYckPBlkq90zrquVJ7Mo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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