SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e7143ba74817dd2d33e86e5ea63adfc252bfc594251850daf758e84c7478ab3' 
  AND token = 'jzKDlhBjF/URzNoHmcUgy3fZ7ydgREIZktbq3KVd/Ns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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