SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a84ea43b69ffd7b5dedb2e0a0638ed281fe0b12781a9c164ba6289759b30ed4d' 
  AND token = 'm4/gkUoYJRlMVnIgls9gBXeUYlSNwnTK+Z6hQSE+P58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00086

JSON explain

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