SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57d27abd72a811803cbcba235a745b53a92bb649a3b29a64166e60b4346f805d' 
  AND token = 'sTyGYh+ewT/edDZJaJHfDxO+GZt2yb6o/3Iske1AMzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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