SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6f09074e1249783cf0ddd2950afc4f74e481242f042e715979390caa23ebd46' 
  AND token = '1bxuV0mSTwGmyJjy72zZCCYvNp5fDcZHjTir+0cTA9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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