SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b5139d3c7eac8162600e1f44fab2499afae83a1623b6561c92d88e576fe1b52e' 
  AND token = 'XpPL+V/geoCkCkFlpzflJi0YDlspCDxQeHAaURiUhl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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