SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3d03ed50663220835d1c15a8fcd36fe373980c8cd5cead3136f3b9013cc36847' 
  AND token = 'lMgQAYy+a3Fwc+UDzXEuqqvNyDvZpfd91oWmrXKTUDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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