SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f94106fb4aa6872814767e943310172498ea7986f14b434b148d79dbc8528b5f' 
  AND token = 'tPC/V8ep5CQBxy935lLqfiuS47kD7yW0dDENwkGCTW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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