SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3f094e985bd97a603ba88d0ebcefc3473353176c38aeafded360f0da0863a98' 
  AND token = 'GnQhk4Dr+t8nftFS4O1aEVx9oPqRY+mOgLE0mrB/BhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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