SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6cc073333304b6bda1f1483dda2f638e553254212d7c13215d36448e2bff29d2' 
  AND token = 'edMybkKnMn3tyyFOgW7l8Zei+MV+ikXHhMI2GsaeHks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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