SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34048ce033986ed5eee6d3492b0e7cb1877d854549179f2b12729857e87e4235' 
  AND token = '3XoKDej+egjgIgEK46IWnpJJGVS9Ge/lRDsDqcNVA1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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