SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c4e3cfa65d0ce29f547ca412e718bacd19961894564bc561a381e9e13406955' 
  AND token = '5trlK+mW+3AKlCyYssDpUlcuEPFC5GqYTIaaXUpVzLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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