SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc6fed0b741fc9a9b572e29baa0fe430b51413f889501da466c8f3dd9967c6f8' 
  AND token = 'SvQ/nGzimfY6XVj3E4UHuZwW5RgWGJ1ZJxN7IyO1grE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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