SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '28b8dc61fb74fb2137bb400f195fe46cdd6f21821fd2d86cef4a4ba80fe7cd6b' 
  AND token = '3fJqnZ5dWvNF6p8+CZ7v/hDLqZbWdGV0OPLhr2g9kj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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