SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4200d8d50a6e0d4891906e47e88f12eb0c3df8eedf12db6c3a7cb93f85f66cf0' 
  AND token = '6ip1bRdi9j6bbEEXotWETY2CwURnS/5WjmccWA3qqdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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