SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38239f2393e827d553216e97799bd8df8a81a6d25676528fba4c6e7ed544545d' 
  AND token = 'urHYcqoNdnvudmDTs/EhfB/ns2kuF4MkIgJOKQBSjS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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