SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61c2bb3d57ee286187c4c7d217f73558ed54e8a425975b229238c6052bbef28d' 
  AND token = 'Y5O/S/yCg2BeKd3ajwrVhffyBlsoU7yfWzVwBL9VXQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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