SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6345260d955015f2f7c8c1a43bb0cbdc317e84463ae635bef506547ebe9411c6' 
  AND token = 'FfLxP3uBvDawmTAnx/CaK+uJCPjJ3Uk3+q5iNvGpNwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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