SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ebdd61a60effffa99122a96f22faf7bf2992980a4b1ea131239eb2ca0a65b30' 
  AND token = 'gEcD5rj9etRbJKtRUQ8avsKDRzf35ang5cFviFKgrH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}