SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e6849b2057df3e83ba3516ab69ac11c0acbbea19e235187376738992863f6c4' 
  AND token = 'n49VxAy7Xlqp9D8z5fywEYWFGE09l/fvu0jqT7VqZVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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