SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4adcc6c8a716acaa019c28ed8b5c00e869f50a0398e0421d09076131c00842a' 
  AND token = 'qLTKn0+MxhGkrxS6FrEcZNkxDQ0bK+e1n623HUFf+TA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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