SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '16fbf8cc8289cd35fc6d7650f183c4eb356c99839a8a9204d2e3912659594bc3' 
  AND token = 'yG3dxzfaOOYa+vln8cRSV/4KPUTvr4oCtoQHdmH3tIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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