SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b8d527eda092cc216806320fd6c5016df16930427c8fee8d93e23f8feefad7f5' 
  AND token = 'gtTsbiVh64j5KNJ2Oqz0HCGgMCaPw8Z1Bqfob8p7fWk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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