SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '102fe67a9a0ef53aed2cb9ee9ced2e03f51989efc2824684a574fd52f1400de6' 
  AND token = 'xshzn0pIvuAZ+o7VQGt2yNh/v9enJxTVHCyZhUAjqJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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