SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba6f4346652197b33dc5fba32af8506852f3d50c1fa51e60cf097c6e0a8f4a83' 
  AND token = 'jTIPl7Kmtcnejpal5zkv48vGgOAFUJzLnpMGe9UcleM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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