SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ff8c5331bc3a25ea1721aa13427a42a382e0f349e21b78ba9c18660b3972b8c4' 
  AND token = 'WpyLEtH8zj+YAmZim++J8b9WzFaCY7N+Ug1yC2sCZ0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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