SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '957b9fd5b80744c1b4969f60dc47b7cb1aee5590990bcafbdcfe660e440f7751' 
  AND token = 'V0c3zOZ9eaH09SCmmupuBk00hHi2JHhRWeUwC3AOrek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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