SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99dffbaf099e7bf3800f04d2502f24512a7485809318d02865b211fbfeac8cf3' 
  AND token = 'lqIH+kumyIpHfbLXxFEdt8KQJllEtOT3VcZnLvxDUTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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