SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86f3b14f2dd575299da85fce19b5aa49683e278af00b848897ab7e25517ba179' 
  AND token = 'dxlCl22EcaqsFgacPljXVR3Kq1vGMWj+jmnrrQrrjgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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