SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '805f8a3557df7eb2e1d58826b4e520c2b4873badbe06fa67c496576f7b836600' 
  AND token = 'mNx2AxgCGGskqoieZh7s5GvPwZqzu2JdEDxjNmaRWpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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