SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24d72934c30657f60aa54bc425a90b09d7c08bfc910940beceea5f26a17a8b94' 
  AND token = 'l042FC+XPIDoBxfBlZ24KylI9QaeodeRKV8wLJHTA2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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