SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb8bea9f19457043a7783f28b4f8acbeef56b7dc78332ae038eb2ec84c02077b' 
  AND token = 'gXnvZ9d7+WwZ1XpWDGWpGUEayJvzFrt2oH5VGIK2mqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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