SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c56fe1099600dd703418522932b378402d5a8ff23dcf0a97f62f7284c2dc251' 
  AND token = 'MEnTYJh0COLg4C9oXdiIaaOEXUxYP56vedCFkUO2ylw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}