SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a91b85a4046fbac1646bceda384cf870f2121ae7877fddb8575f7aac16f4418' 
  AND token = 'fiSR5NkwpLUpK6vDwRfUY+yx00CSZ2oMq0cI9BFZRww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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