SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc31a4f40fc56601d5de6be159ed75278ad14e8d4cba6f5765ab7e8388f4ebbe' 
  AND token = 'YI4VTpVX+2RUZ5/Lz/MVZh+hVYK5GSQIVCjxzqmAJH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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