SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b38c29a387239186e8951c7749854bbef7ff138212204b6d9273a4680a2778c' 
  AND token = 'TOa9up0tr4yVuahZzi0MJSwQukK1H/1OHy5eTJBMv/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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