SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db411837acdf295ab5890feefd3087af9e15ced4a941f7662fba361bddb4898f' 
  AND token = 'T/+fZYVoUFn/7/iPdiwEgl5u++j84qElYXh2MMObF2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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