SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5e4c502356ebfa97549cc0793b86f1032383a82bd08917e80b6a4f23db5f5d41' 
  AND token = 'k51GgdZF2pFwJGoapPtukVm4Cp4hNOAIx1jXfg4BYyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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