SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b5b80629787effe79b9bfc5669f136e02fb6a7f2e8341ef00813d3eaea3ba13' 
  AND token = 'b83V6BO2/L8XpzM/GLlZhhDYz8DFROiTIZijq7SgD0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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