SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73be9fc459f71a5d65fcabb91578dab105bdf6d03c08b3a6d9d680f1fe4ee629' 
  AND token = 'A3/TATSOFXUXiYpjpohRMNwKgpyuzJBjo6Vr/rE2L2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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