SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18e6b1951009b3f3fedc3b7852b968dfb07ae2bdf2d5dde7aaae7ec474423b4f' 
  AND token = 'FZOaKI3JQlujwh0PJY+7ZGOL+23Ype/E5zEjq3evg4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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