SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b935acb455d9ef153b6bd04e6b50563e9f7e0d5c8fbabece45fa8bfe8f96015c' 
  AND token = 'hFJmrB1tnD7ow62WhdJ1GfmNfYArzxONNgEfTDutG+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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