SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36efb24bb0613b0a72b5bcd1c49a8b5e14d8255ad35a22d5ff61e547a7db4be1' 
  AND token = 'Wj4VaKn+98vCqSX/MGiLjEpJxPONntn/eCLRCSaPhLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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