SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc49353b14b932beb4a78aa23c68f0f9669db167ac4d53573c518fb9bdfe3765' 
  AND token = 'zPQMrNFIvxgmkK/uvycKqDze7SaNe5AnQxuHrd5+drA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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