SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f52f9c5e8576a85c767235a895a07cf183124040128f02ea71377a857ebba7b' 
  AND token = 'YWZs44UXL38UAcBjeLWuwqQf2r68sGdy7ttkFVwBwkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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