SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b452f43232f1045114e4d4be6f7b235fc9f3128900d8c7bbf8b7b1d162b1dfd8' 
  AND token = 'rsyx/GbORYlsVnHS7odjqHTtkwj8vVF/HqRqkK6UzZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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