SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7d44558b3af31d860716c2f4e8885ef80aa17afe7433f9d191317fba1cb4556' 
  AND token = 'Q8h3BnLsIZHl9AVTKxxhQzGzXie3tZRHghsFgkSl3+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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