SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00a8ddf916a5fef6d61c15f652e0e53d91a1788a2de21363a98e3092e8f698c3' 
  AND token = 'qCahaT4FOxGuMCmAJxk2E/AfIHlRmGlZVjqjXG2CYvw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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