SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e18f0924d79214af351c935d6bd511848998f00e7b715dcc77299369843c9bb4' 
  AND token = 'tdDOvfG31aek9Nxablf0W+VXlhG6AEH/mq1ZHXecGmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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