SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '754a08ccf52ca522d9e46db305ce4d533d42b87d276fda7d9fc3ea76152a96bc' 
  AND token = 'nEwryYs+/25sQ6oA/ZDu6m73iNdGiLDEU+SH1uAoQds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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