SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '321680a20e7e49b42dad78bfa27cbac2967daae53918b2b69fbcaa72cb9d1d73' 
  AND token = 'qOPMVGBCDwG4SDAtCFsWfwHz0JoxZAlcUC+EV4RsuxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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