SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cf352808785bcc838feef9ac662b72ca99bfb81512615c50eb3d5dc463617a8' 
  AND token = 'BKAvjqG/7peNrNkCW+6oUf9IajGbuY4AO5a2MFLRlDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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