SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa58a4d914af89c5fe0288b9681ca6edba671c04a98877f0381baa8711828160' 
  AND token = 'dRl6gzGKVqBNhNI7QEYv6sYtdcXzutp00d3V6zyElC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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