SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8bef427e7412a1133800de00b1927ec2210200089c0d7711b03efec5c92789e' 
  AND token = 'v9l6aLwbWVizmryYt/+acjZkeIKL7h0Ce+/HGQUVEB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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