SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c85ec94c223d09bcbb5b41b21f5da6f02d8f58daf1989606bc872428bbcfc19' 
  AND token = 'CUzqIlj4FHbgYvmfwi+3IuiihFcKkhveZupux0UGD7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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