SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd04b2f4fb9ba0901b40af46f537fa4b1ce8988a07b18e8b64b2e21c4aca7b8f6' 
  AND token = 'GMYpKjiSq2mCBBDAhZV1OXAxGv6q6cDlb29rgUNw4oA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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