SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3d18b618db4c549cd39bbd81d530109c024eb005457d3d039143f0e4df18158' 
  AND token = '2SZ0kzIBge6rhKajR6pEcKup6DR0FYjSMyFTKFhrdoc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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