SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e376b8d436165dd3879e45cb6d8cfcff18563b4bdf932bab237b64aecea10b1' 
  AND token = 'cKsDccpXeP8hHHInUNzF1LCM0E8QnALeNhYHluZm5CA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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