SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '956c8612f6b9673d2735b64fd4b77c0704abd596bc143b9558a474e4c96cf6bd' 
  AND token = 'U/zO+EGhuSMFVWoaI1GXvcgA/Cfas2CDXJDD1F/BVAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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