SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c5759e2268044c06855d90317f8081d6b7bef789303738a2a19b96333eddafd' 
  AND token = 'u/dSWMIFZSnYzwE6pLgVvjjXFGMwB7w35XjbzY8vs30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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