SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31b8f27c0fd2d3ba7848f8001266841b2b6b228532ebdc56415cae8b20004643' 
  AND token = 'WuRupkKDgjwwNiDWcBSShuoQxLCRX9duK2iJwEaRT0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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