SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5aa875089a689365435a28f638562484cb3d69ecd49a02d1156aa9c26b30064' 
  AND token = 'S8ufnRK6f7olSCyaBxNzA7ztZBI7NGvkZgoNWWtpNx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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