SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0083d6c18e288ca48bc73c36ebd0be20143bfabb1692a3bf1a1b242c3141078' 
  AND token = 'ONjPZxUaF9//PpmupwHmOQfI6q8okbqoC4aEIoXF/hY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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