SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04735a1a9c31ce7b6f6b8c0160a4accbbe05f07c946501ead2850f53b726d0ec' 
  AND token = '1UbtrFVjEU6i5jbBtpwK3kBz2Qe7/HpBepIB3QH+i68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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