SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f39107386cb754edd5f0738c3356b13792aab53ea173860796e49977acb3d6af' 
  AND token = 'dhsWZcPeqcTZN7/SG1OpjMqnII3nMil0RJM1KAAmhTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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