SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4baccd828d79b3e08f971ca947e9c40acc2dd36e572016d12cff1dd3b29d4ed2' 
  AND token = '985xzTHs1sSnSUlBhR/icWOFtzhKIfwLzVevZQ2mJqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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