SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ef79348b6fccd5001c56f5fb714f9217d90657897f9c92f85ac7734d2377a65' 
  AND token = '7Q91fncExy7u7mWhFrXUr7mL5HKnG9RxmeLG63DtHxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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