SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fdba6c684078a70b58f5a72536653a3f91959e1fc49dece4abf25369e313151' 
  AND token = 'rlMXboNWl3FRvXNFuYz4xwYj6rlaECrBmD3eInq46Ho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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