SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6901bc5addae08679a22e334c062226546b74223b94295922ee8c0d252412558' 
  AND token = 'TSmYG14dpss/3HvToHsnyHSiYnGs5AOmVxmwFccMIXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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