SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bde65ac398abb170dceed80ddf1341ee63965a715fb7f9119849224fc88bb4d' 
  AND token = 'vvzZfaSaptkZk7cNIWREhj+KQwIOJ2DzQF0W+jVTrG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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