SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2588ac13e48df45d1ce3d9caf6b594ba715a2cb55516a92a93256e4733767076' 
  AND token = 'Oo5J9NAFVP+Xwko0gnHl5VueVscdS4r1BBNjpUY/41A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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