SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2346f689a0dd1d0a0dd379ce91da34550f2530814d165fcbbf252bb82e366b1' 
  AND token = '43svYXQDgL48jZ1v4zNJ4LpdC0NSPj4CldaTrPQM+NY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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