SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a3469243fe4faed3f7c3c4e7319cbd3e003ea6d8fae509756b8362ab82493b2' 
  AND token = '6tDhTht+Y/lEMQrRK5So9jF9TqO8/Jk9rMunYjwZzB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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