SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '191a164ddf565f9b815a724de274159ed7c639221bfdc5783e07068bc51ce307' 
  AND token = 'kffARn/DZxdpb7Nph5n5At8IOcMStrP/mSUAxNbxK7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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