SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f720d85ac7dc4aedfc686482bdb0c9dde0a3c76f45232f0f4ad84d192557d143' 
  AND token = '+78t/UivszhDq3Ipi5ZEzQvyjirxax/pK7hz+B06XFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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