SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2ea7114466ea80827c888c1ce9644d53f11963225a3c830e38dff583440bcd8d' 
  AND token = 'HscW0uJQgJWXoD5UxsOo8s5zQg4jSdvAwG6okudxXj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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