SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bbaa21005a5779a8bbd6d05875f3525a748f26986907101796e3e5c3c5f55e4' 
  AND token = '65wT62U1NmjL8183gHeeh2ky8dSCiUC5nMOfed7BplU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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