SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd638c3fbe438050f8c997134a3d9c15249237c34b44093be97d97fcc518f7f2d' 
  AND token = 'Dwr5ownY3UYNAwzmMqqpHDdsRdsNiD1VJhjHVB3K2tI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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