SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92615d99dccf172f7ce9f8fefd6855107e8d84bd311b595dff6bda61fa9f9b54' 
  AND token = 'xpnCFoOOeEjwcUVtzaUzfUibxPrgycdk94L6e9EmB64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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