SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1fa0834cbd465ceb82a87d5b34649848066bc5e0b31ec23c77004fbf9d7f3a3' 
  AND token = 'gu55xa9N4Az/KXseNLm/tQTtmVLEjcBKhQ/Dd5qGlKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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