SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '642389865a81c95044db92c5950616322ac7f6e4baa8c628c8a897068cd30a46' 
  AND token = '+pRa3ECrVx5s7w86b8kjxTKKbubAoL2bXwxejfRnTl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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