SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f7dae60619f08f5ed1c94b317bab30f4a2601ecf02fdb0c7f7836bb36a246568' 
  AND token = 'ZKElfVeCwBXE5noPTYUtim2oBvDLkdF7+LPHAh1ue3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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