SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '848bd97cd8695768c5e242abc99be2e15cfec9bbd51e409f122d316148db9b9b' 
  AND token = 'nkScMmRz0tTvkuBuEgv5j/vEJfZ61JRdNH6n2z50OGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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