SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96eadd3baa6e532ec248758b403e115b99e80ed44fea60aa9b407ff544720f49' 
  AND token = 'KiVsR3dED0ouEJJ1c+W3gRm1gBTVHNMs2S+cFg5P3l8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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