SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee529c35fe8448ee62f864a762104659d567f0f8290b2dbd2a4fe73b9ffd2980' 
  AND token = 'DoI9w2lKqTQMwknDCKBESyVjqAFD96fFETdlZIGOd6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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