SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67b6f9b8672d7ec58d09aaee99063a19f504b5a51347dd7f51a87324db4e08f4' 
  AND token = '08m/qLM7vVyQhUvb47EJolCPuYWkzkMzNitO3hb+eJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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