SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '965f1114a4869501793391b0149f5975f1abaf73609aa1ad705132aa17c9e085' 
  AND token = 'CtSvTONxyN360WgnJ27+ibJPb+Se+jliHwGWRIitAZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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