SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f34b766bf788db49725fd31824368123fdad986b0e295afeba62320bdc6a247c' 
  AND token = 'aX8cf8tJkPlHh+luvvhAfTZRklTmnvf3tg2A659vd78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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