SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84429b1919d1e7ccee2f80a183e075f629f24f63d60afa8cc6f3fd831ad8202d' 
  AND token = 'ErK4plbf01ebaRuqnLJYtnsyECvNmsDyd9ChzeVgDYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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