SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd038c98d9f281a99624cfc0236837f58f922bbe9b1fda4e36138125453a6a7aa' 
  AND token = 'Mk4nk659KtWJN0m9+g9Q/1RUThPgz28uB/5HYjkFbpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}