SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1511ec7b047fb2783340328b042f5e5daee72f8f2af2e5deaa8a8cabc72ba487' 
  AND token = 'zmjk42nHexUFeGIX858QYGleU/SHHF+OYLxRTkg25NM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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